//! Database built-in plugin
//! 
//! This plugin provides database connectivity and query functionality.

use super::BuiltinPlugin;
use crate::error::{Error, Result, StorageError};
use crate::models::{Value, ValueMap};
use serde_json;
use std::collections::HashMap;

/// Database built-in plugin
#[derive(Debug)]
pub struct DatabasePlugin {
    /// Plugin configuration
    config: ValueMap,
    
    /// Connection pools (placeholder)
    connections: HashMap<String, String>,
}

impl DatabasePlugin {
    /// Create a new database plugin
    pub fn new() -> Self {
        Self {
            config: HashMap::new(),
            connections: HashMap::new(),
        }
    }
    
    /// Connect to database
    async fn connect(&mut self, args: &[Value]) -> Result<Value> {
        if args.is_empty() {
            return Err(Error::Storage(StorageError::ConnectionFailed {
                reason: "Missing connection configuration".to_string(),
            }));
        }
        
        let config = &args[0];
        let connection_name = config.get("name")
            .and_then(|v| v.as_str())
            .unwrap_or("default")
            .to_string();
        
        // TODO: Implement actual database connection
        // This is a placeholder implementation
        self.connections.insert(connection_name.clone(), "connected".to_string());
        
        Ok(serde_json::json!({
            "status": "connected",
            "connection": connection_name
        }))
    }
    
    /// Execute query
    async fn query(&self, args: &[Value]) -> Result<Value> {
        if args.len() < 2 {
            return Err(Error::Storage(StorageError::QueryFailed {
                query: "".to_string(),
                reason: "Missing connection or query".to_string(),
            }));
        }
        
        let connection_name = args[0].as_str().unwrap_or("default");
        let query = args[1].as_str().unwrap_or("");
        
        // Check if connection exists
        if !self.connections.contains_key(connection_name) {
            return Err(Error::Storage(StorageError::ConnectionFailed {
                reason: format!("Connection not found: {}", connection_name),
            }));
        }
        
        // TODO: Implement actual query execution
        // This is a placeholder implementation
        Ok(serde_json::json!({
            "status": "executed",
            "query": query,
            "rows_affected": 0,
            "results": []
        }))
    }
    
    /// Close connection
    async fn disconnect(&mut self, args: &[Value]) -> Result<Value> {
        let connection_name = if args.is_empty() {
            "default"
        } else {
            args[0].as_str().unwrap_or("default")
        };
        
        self.connections.remove(connection_name);
        
        Ok(serde_json::json!({
            "status": "disconnected",
            "connection": connection_name
        }))
    }
    
    /// List connections
    async fn list_connections(&self, _args: &[Value]) -> Result<Value> {
        let connections: Vec<&String> = self.connections.keys().collect();
        Ok(serde_json::json!({
            "connections": connections
        }))
    }
}

impl BuiltinPlugin for DatabasePlugin {
    fn name(&self) -> &str {
        "database"
    }
    
    fn version(&self) -> &str {
        "1.0.0"
    }
    
    fn functions(&self) -> Vec<String> {
        vec![
            "connect".to_string(),
            "query".to_string(),
            "execute".to_string(),
            "disconnect".to_string(),
            "list_connections".to_string(),
        ]
    }
    
    async fn call_function(&self, function_name: &str, args: &[Value]) -> Result<Value> {
        match function_name {
            "connect" => {
                // This requires mutable access, which we don't have here
                // In a real implementation, we'd need to handle this differently
                Ok(serde_json::json!({"status": "connect_not_supported_in_immutable_context"}))
            }
            "query" | "execute" => self.query(args).await,
            "disconnect" => {
                // This requires mutable access, which we don't have here
                Ok(serde_json::json!({"status": "disconnect_not_supported_in_immutable_context"}))
            }
            "list_connections" => self.list_connections(args).await,
            _ => Err(Error::Plugin(crate::error::PluginError::FunctionNotFound {
                function_name: function_name.to_string(),
            })),
        }
    }
    
    async fn initialize(&mut self, config: ValueMap) -> Result<()> {
        self.config = config;
        tracing::info!("Database plugin initialized");
        Ok(())
    }
    
    async fn cleanup(&mut self) -> Result<()> {
        self.connections.clear();
        tracing::info!("Database plugin cleaned up");
        Ok(())
    }
}

impl Default for DatabasePlugin {
    fn default() -> Self {
        Self::new()
    }
}
